Just hours after suicide bombers attacked the Iranian embassy in Lebanon’s capital Beirut, killing 23 including the cultural attaché, claims of responsibility and accusations started flying. The al-Qaeda-linked and Lebanon-based Abdullah Azzam Brigade said they were behind the attack, according to a tweet posted by the group’s religious leader Sheik Sirajeddine Zuraiqat that was picked up by Reuters. But the Iranian government immediately blamed Israel, calling the attacks “an inhuman crime and spiteful act done by Zionists and their mercenaries” in a Foreign Ministry statement released by the official IRNA news agency.

According to Reuters, Zuraiqat threatened that the Azzam Brigade, which takes its name from Osama bin Laden’s Palestinian mentor, would continue its bombing campaign until Iran pulled its forces out of Syria, a likely reference to the Iranian-backed Lebanese Shi‘ite militia Hizballah that is fighting on behalf of Syrian President Bashar Assad. The Iranian embassy is located in the heavily Hizballah-dominated southern suburbs of Beirut, and today’s attack follows on the heels of a similarly devastating car bombing that killed 27 people on Aug. 15 in the same area, also in retaliation for the militia’s support for Assad. In response, two bombs in the Sunni stronghold of Tripoli in northern Lebanon detonated on Aug. 23, killing more than 40. The tit-for-tat blasts have sparked fears that Lebanon will not be able to resist falling prey to the civil and sectarian war that has engulfed Syria.

Investigators with Lebanon’s military said in a statement that one of the attackers was on a motorcycle while the other was driving a 4×4 vehicle, possible evidence of an attempt at the kind of complex attack al-Qaeda is known for. But even if suspects do end up being detained, the identity of the attacks’ mastermind and principal financier are likely to remain shrouded in mystery. In Lebanon, political considerations have a tendency to derail investigations that get too close to revealing potentially destabilizing information. Nearly a decade on, even the 2005 car-bomb attack that killed former Prime Minister Rafik Hariri has yet to be solved, bogged down by accusations of tainted evidence and politically motivated witnesses. In the case of the Iranian embassy bombings, claims of responsibility are likely to remain as credible as accusations.

Blasts Near Iranian Embassy in Beirut Kill Dozens

AFP / Getty Images

Flames rise from the site of a blast in Bir Hassan neighbourhood in southern Beirut on Nov. 19, 2013.

Aryn Baker is the Middle East Bureau Chief for TIME, covering politics, society, culture, religion, the arts and the military in the greater Middle East, including Pakistan and Afghanistan. She currently resides in Beirut, Lebanon.